Date: Sun, 22 Dec 2013 00:46:04 +0200 From: Guy Yur <guyyur@gmail.com> To: freebsd-arm@freebsd.org, freebsd-net@freebsd.org Subject: Re: 10.0-RC1: net/mpd5 crashes in NgMkSockNode due to stack alignment on ARM EABI Message-ID: <CAC67Hz-U-CgC6VgTsj4WpKGdGh7aGWVmBneiN8sangVwuh_4pw@mail.gmail.com> In-Reply-To: <20131221191552.GE99167@funkthat.com> References: <CAC67Hz82VBT1_BBH6E18ycDxUdWbgFcahNo1W0kH-TcH7iB=8Q@mail.gmail.com> <20131221191552.GE99167@funkthat.com>
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--089e013c6fa0e84e3904ee132880 Content-Type: text/plain; charset=UTF-8 On Sat, Dec 21, 2013 at 9:15 PM, John-Mark Gurney <jmg@funkthat.com> wrote: > Guy Yur wrote this message on Sat, Dec 21, 2013 at 19:24 +0200: >> I am running 10.0-RC1 on the BeagleBone Black and the net/mpd5 port is >> crashing in libnetgraph NgMkSockNode due to stack alignment. >> >> 10.0-RC1 World and kernel were compiled in a VirtualBox VM running >> 9.2-RELEASE-p2 i386. >> clang and ARM_EABI used as the default make options. >> >> Added prints in NgMkSockNode show rbuf is aligned on 2-byte and not >> 4-byte which is needed to access ni->id (a uint32_t). >> >> ni = 0xbfffe87a >> rbuf = 0xbfffe842 >> sizeof(resp->header) = 56 >> >> >> (gdb) bt >> #0 0x201529a0 in NgMkSockNode (name=<value optimized out>, csp=0xbfffe95c, >> dsp=0xbfffe958) at /usr/src/lib/libnetgraph/sock.c:134 >> #1 0x00037b9c in MppcTestCap () at ccp_mppc.c:754 >> #2 0x0007c1f4 in main (ac=4, av=0xbfffeb90) at main.c:248 >> #3 0x0000d1b0 in __start (argc=4, argv=0xbfffeb90, env=0xbfffeba4, >> ps_strings=<value optimized out>, obj=<value optimized out>, >> cleanup=<value optimized out>) at /usr/src/lib/csu/arm/crt1.c:115 >> #4 0x203e9dc0 in _thr_ast (curthread=0x200fd000) >> at /usr/src/lib/libthr/thread/thr_sig.c:265 >> >> >> Putting rbuf in a union with struct ng_mesg sorted the alignment to >> 4-byte and mpd5 didn't crash. >> I attached the changes I used to test mpd5 doesn't crash with correct alignment. > > The patch looks correct, but lets make sure that the -net people don't > have an issue with it... > > I've reattached Guy's patch for review. > > Guy, bug me in a week or so if I haven't committed it, and I will... > > Thanks for tracking this down. > > -- > John-Mark Gurney Voice: +1 415 225 5579 > > "All that I will do, has been done, All that I have, has not." Hi John, Should I still file a PR? 1. I noticed my patch causes a style bug with the rbuf line now taking 87 columns. 2. Since the union now has a ng_mesg struct, the casting to resp can be skipped and the union member used directly. Attached new patch breaking the rbuf line and swapping resp usage with res.res and &res.res Maybe a different name than res should be used for the union or the member. I only tested the new patch compiles for arm.armv6, haven't verified it. Thanks, Guy --089e013c6fa0e84e3904ee132880 Content-Type: application/octet-stream; name="sock-NgMkSockNode-2.patch" Content-Disposition: attachment; filename="sock-NgMkSockNode-2.patch" Content-Transfer-Encoding: base64 X-Attachment-Id: f_hphga6do1 SW5kZXg6IGxpYi9saWJuZXRncmFwaC9zb2NrLmMKPT09PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PQotLS0gbGliL2xpYm5ldGdy YXBoL3NvY2suYwkocmV2aXNpb24gMjU5MjUwKQorKysgbGliL2xpYm5ldGdyYXBoL3NvY2suYwko d29ya2luZyBjb3B5KQpAQCAtMTExLDkgKzExMSwxMiBAQAogCQkvKiBTYXZlIG5vZGUgbmFtZSAq LwogCQlzdHJsY3B5KG5hbWVidWYsIG5hbWUsIHNpemVvZihuYW1lYnVmKSk7CiAJfSBlbHNlIGlm IChkc3AgIT0gTlVMTCkgewotCQl1X2NoYXIgcmJ1ZltzaXplb2Yoc3RydWN0IG5nX21lc2cpICsg c2l6ZW9mKHN0cnVjdCBub2RlaW5mbyldOwotCQlzdHJ1Y3QgbmdfbWVzZyAqY29uc3QgcmVzcCA9 IChzdHJ1Y3QgbmdfbWVzZyAqKSByYnVmOwotCQlzdHJ1Y3Qgbm9kZWluZm8gKmNvbnN0IG5pID0g KHN0cnVjdCBub2RlaW5mbyAqKSByZXNwLT5kYXRhOworCQl1bmlvbiB7CisJCQl1X2NoYXIgcmJ1 ZltzaXplb2Yoc3RydWN0IG5nX21lc2cpICsKKwkJCSAgICBzaXplb2Yoc3RydWN0IG5vZGVpbmZv KV07CisJCQlzdHJ1Y3QgbmdfbWVzZyByZXM7CisJCX0gcmVzOworCQlzdHJ1Y3Qgbm9kZWluZm8g KmNvbnN0IG5pID0gKHN0cnVjdCBub2RlaW5mbyAqKSByZXMucmVzLmRhdGE7CiAKIAkJLyogRmlu ZCBvdXQgdGhlIG5vZGUgSUQgKi8KIAkJaWYgKE5nU2VuZE1zZyhjcywgIi4iLCBOR01fR0VORVJJ Q19DT09LSUUsCkBAIC0xMjMsNyArMTI2LDcgQEAKIAkJCQlOR0xPRygic2VuZCBub2RlaW5mbyIp OwogCQkJZ290byBlcnJvdXQ7CiAJCX0KLQkJaWYgKE5nUmVjdk1zZyhjcywgcmVzcCwgc2l6ZW9m KHJidWYpLCBOVUxMKSA8IDApIHsKKwkJaWYgKE5nUmVjdk1zZyhjcywgJnJlcy5yZXMsIHNpemVv ZihyZXMucmJ1ZiksIE5VTEwpIDwgMCkgewogCQkJZXJybm9zdiA9IGVycm5vOwogCQkJaWYgKF9n TmdEZWJ1Z0xldmVsID49IDEpCiAJCQkJTkdMT0coInJlY3Ygbm9kZWluZm8iKTsK --089e013c6fa0e84e3904ee132880--
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